package org.apache.helix.recipes.rabbitmq;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  import java.util.List;
  
  import org.apache.helix.HelixManager;
  import org.apache.helix.HelixManagerFactory;
  import org.apache.helix.InstanceType;
  import org.apache.helix.manager.zk.ZKHelixAdmin;
  import org.apache.helix.manager.zk.ZNRecordSerializer;
  import org.apache.helix.manager.zk.ZkClient;
  import org.apache.helix.model.InstanceConfig;
  import org.apache.helix.participant.StateMachineEngine;
  import org.apache.helix.participant.statemachine.StateModel;
  
  public class Consumer
  {
    private final String _zkAddr;
    private final String _clusterName;
    private final String _consumerId;
    private final String _mqServer;
    private HelixManager _manager = null;
  
    public Consumer(String zkAddr, String clusterName, String consumerId, String mqServer)
    {
      _zkAddr = zkAddr;
      _clusterName = clusterName;
      _consumerId = consumerId;
      _mqServer = mqServer;
    }
  
    public void connect()
    {
      try
      {
        _manager =
            HelixManagerFactory.getZKHelixManager(_clusterName,
                                                  _consumerId,
                                                  InstanceType.PARTICIPANT,
                                                  _zkAddr);
  
        StateMachineEngine stateMach = _manager.getStateMachineEngine();
        ConsumerStateModelFactory modelFactory =
            new ConsumerStateModelFactory(_consumerId, _mqServer);
        stateMach.registerStateModelFactory(SetupConsumerCluster.DEFAULT_STATE_MODEL, modelFactory);
  
        _manager.connect();
  
        Thread.currentThread().join();
      }
      catch (InterruptedException e)
      {
        System.err.println(" [-] " + _consumerId + " is interrupted ...");
      }
      catch (Exception e)
      {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
      finally
      {
        disconnect();
      }
    }
  
    public void disconnect()
    {
      if (_manager != null)
      {
        _manager.disconnect();
      }
    }
  
    public static void main(String[] args) throws Exception
    {
      if (args.length < 3)
      {
        System.err.println("USAGE: java Consumer zookeeperAddress (e.g. localhost:2181) consumerId (0-2), rabbitmqServer (e.g. localhost)");
        System.exit(1);
      }
  
     final String zkAddr = args[0];
     final String clusterName = SetupConsumerCluster.DEFAULT_CLUSTER_NAME;
     final String consumerId = args[1];
     final String mqServer = args[2];
 
     ZkClient zkclient = null;
     try
     {
       // add node to cluster if not already added
       zkclient =
           new ZkClient(zkAddr,
                        ZkClient.DEFAULT_SESSION_TIMEOUT,
                        ZkClient.DEFAULT_CONNECTION_TIMEOUT,
                        new ZNRecordSerializer());
       ZKHelixAdmin admin = new ZKHelixAdmin(zkclient);
 
       List<String> nodes = admin.getInstancesInCluster(clusterName);
       if (!nodes.contains("consumer_" + consumerId))
       {
         InstanceConfig config = new InstanceConfig("consumer_" + consumerId);
         config.setHostName("localhost");
         config.setInstanceEnabled(true);
         admin.addInstance(clusterName, config);
       }
 
       // start consumer
       final Consumer consumer =
           new Consumer(zkAddr, clusterName, "consumer_" + consumerId, mqServer);
 
       Runtime.getRuntime().addShutdownHook(new Thread()
       {
         @Override
         public void run()
         {
           System.out.println("Shutting down consumer_" + consumerId);
           consumer.disconnect();
         }
       });
 
       consumer.connect();
     }
     finally
     {
       if (zkclient != null)
       {
         zkclient.close();
       }
     }
   }
 }